The cat-and-mouse type rotary engine includes generally identical two piston assemblies each having a plurality of diagonally opposed pistons that divide a toroidal working chamber into a plurality of subchambers, wherein the piston assemblies are connected to the driveshaft (or output shaft) by a connecting means. The working chamber assembly has crevices that extend circumferentially between the working chamber assembly's housing and piston assemblies and between piston assemblies.
The cat-and-mouse type rotary engine is expected to have two key technical advantages for attaining higher efficiency than the conventional reciprocating engine such that (1) the intake and exhaust port designs are simpler and (2) the engine is potentially less susceptible to knocking. This engine is expected to be much lighter than the conventional reciprocating engine also. But, there is no record of successful development of the cat-and-mouse type rotary engine. This is because, we believe, the engine possibly has or at least is perceived to have problems in the sealing means of the working chamber and in the connecting means of the piston assemblies to the output shaft.
Seal means to seal the crevices in the working chamber assembly proposed in the past include the so called chamber ring or packing ring first proposed by Weed in U.S. Pat. No. 1,328,410, and later improved by various inventors. Connecting means proposed in the past include the use of a sun-planetary gear and crank mechanism by Kauertz (U.S. Pat. No. 3,144,007) and a modified sun-planetary gear and crank mechanism by Bakhtine (U.S. Pat. No. 6,305,345).
The chamber ring (or packing ring) has never been tested as far as the present inventor knows. The connecting means invented by Bakhtine, though it is an improvement over that invented by Kauertz, is expected to cause unnecessarily large amount of frictional loss by the sun-planetary gear sets especially during high speed operation. This is because Bakhtine's connecting means comprises two separate parts wherein each of which parts is disposed in each side of the working chamber assembly housing and thus the planetary gears of the two sides are not connected before they mesh with the sun gears, and thus the planetary gear in each side has to take the maximum rotational force of each piston assembly independently of the other planetary gear.
We designed a new cat-and-mouse type rotary engine that does not require the use of the chamber ring (or a packing ring) to seal the working chamber, and that does not generate an excessive amount of frictional loss in the connecting means. The new engine is equipped with a means to attain a variable compression ratio and/or a means to vary the number of operating cylinders (or working subchambers).